Primitive Archer
Main Discussion Area => Bows => Topic started by: arachnid on October 17, 2014, 07:59:58 am
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Hi Guys.
I have a white oak board that I want to make a set-back handle + reflexed tips bow from.
Since it`s the first time I`m steam bending, I`ve made a rig and steamed a piece of the board,
about 3/4" thick, just to get the hang of it. I steamed it for about 50 min.
I then took it out quickly and put it in the form. I started bending it slowly and about half way- the belly side cracked! >:( >:( >:(
Here`s the rig:
(https://lh5.googleusercontent.com/-yGBoK4VmD78/VEDiCZVrfQI/AAAAAAAADEo/EipET8RV36Q/w1153-h865-no/20141017_123035.jpg)
The crackes:
(https://lh3.googleusercontent.com/-wi3aj7N7qyg/VEDxZw2fsCI/AAAAAAAADFI/VscdYmfryOk/w1153-h865-no/20141017_133637.jpg)
(https://lh5.googleusercontent.com/-p7exo3ujdi0/VEDxo8GntFI/AAAAAAAADFU/gE5IkjZPef0/w1153-h865-no/20141017_133643.jpg)
So....
1) Am I doing something wrong? Can it be a grain runoff in the side?
2) If this happens on the bow stave, can I scrape the cracks and glue a thin laminate piece on the belly? Will it hold?
Thanks...
Dor
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Being that you are using a board the splinters are happening along the grain lines. A metal strap along the back will support it and help prevent the splinters. Without seeing this first hand I'd say you could super glue and clamp the cracks and continue on. Looks like you will remove most of it when you educe the tips.
A stave is unlikely to splinter like this because you will be bending un-violated rings.
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Thanks Pat.
I thought of a safer way to make the bow- steam bend a set-back in the handle area (that`s a small bend so it shouldn`t be
a problem) and instead of bending the tips, I`ll glue a thick piece on the back of the tip and cut it into a reflex shape with
a bandsaw. That should give me a static-reflexed tips.
Will it have the same effect or steam bending the tips is still my best shot?
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There really isn't one way being better than the other. If it works, go for it. You will still have o consider grain and make sure your scarf joints are long enough to support the bent tip.
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Ok, thanks man.
;) ;) ;)
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Like pat said you need a strap of metal on the belly of your stave to keep splinters from forming.
You also need to alter your bending form to have several c-clamps clamping the wood at arc of your bend, which also help put pressure on the belly to keep splinters down.
When I bent this bow I popped a splinter in spite of having a strap and several c-clamps. I bent a piece thinner osage on the same form as I bent my bow on and glued it to the back of the bow.
My thinking was I would reduce the cracked belly and have plenty of wood because of the glued on piece. Turns out I didn't need the extra piece after I thinned the tips to their final dimensions but I liked the look so I added some walnut to make a fancier effect.
(http://img.photobucket.com/albums/v181/ekrewson/bow%20making/sexystatic001_zpscbd5d64f.jpg) (http://smg.photobucket.com/user/ekrewson/media/bow%20making/sexystatic001_zpscbd5d64f.jpg.html)
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If u work the tips down before u bend it wouldn't crack as bad. 3/4" is a lot of wood to bend.
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Metal strap makes %80 improved bending. Also you may be loosing heat to the box also. Try using a section of stove pipe. the cheap shiny stuff.
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for small sections, like tips, I just make a tent out of tin foil in lieu of the whole steam box. Works just fine. Russ
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you might try steaming a little longer also
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I usually steam 10 mins and have never got a splinter like that but I use staves and usually can chase the spot to one Growth ring. Where you're reflexing looks like a lot of rings run of the edge which could be the biggest problem
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Somewhere in the back of my mind there is a little voice that says that steaming too much is as bad as not steaming enough. Has anyone else heard this? I've looked on the net and can't find anything.
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i am sure there is a point where you steam too much,, but the wood needs to be hot enough to start to bend,,, just like dry heat,, if you dont heat enough it won't bend,,just break or splinter,, you can always bend a little at a time ,, and not make the bend all at once,, being able to steam the whole clamp helps,,it is easier to start bending before it cools,, I also found boards with run off more difficult,,,, i know it would take more time,, but try a piece 1/2 thick and steam for 30 minutes longer and see how she does,,,,the window for bending is not big time wise,,,, keep that in mind,,
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If you soak the wood for a few days you will have much better luck.
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Jo I'd like to see you bend a big static like he's trying and only steam it ten minutes, for those big bends I steam about an hour and bend all at once, about 5/8" thick and two clamps
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I agree with bubby, I've made several static recurves and have had splinter problems on all of them.It seems that if you steam longer=less splinter, start out with enough that you can reduce the tips. I've taken tips that splintered from 3/4" at bending to 3/8" at finish, you will usually have enough thickness before the tip that you don't need to worry about it. I've also done overlays, and buildups and even bending on the same form, there are always minor glitches you have to correct.
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1. Your steaming setup isn't the best. You loose a lot of the hot steam you want in the wood damping useless in the air.
2. You need to have your steaming setup and your jigs/caul near together, the bending must be done inbetween seconds!
3. use a steel strapp as suggested
4. the bending area should have no more than max. 12-15mm (looking at that big bend)
5. you could help the wood bending with a heatgun to hold temperature in the steamed wood
and yes look for a straight grained piece with no run out, as mentioned before.
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If you leave the tips wide and sand the edges quite round it will help. With splinters.i use marc st Louis localized steam method for bending tips.clamp the tip on a caul, place a wet cloth over the area to be bent,cover with foil and heat with a gun.by applying downward pressure you will feel the wood starting to give in about 5 to 7 minutes.i only use about the weight of my arm as pressure.works great with elm, not sure about white oak?that being said,i havn't tried that aggressive of a bend before,albeit close though.
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Thanks a lot for all the great tips guys.
That was only a try-out session, to get the hang of steam bending. I know that
board is not the best, but the real board I`m making the bow from is
better. I`m happy to know that if a splinter like that happens
on the real thing, it`s not lost....
Well, I`m off the the work bench, wish me luck... ;) ;) ;)
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I've yet to try this, but could you boil the tips? I would think doing that would make them like rubber. Patrick
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Patrick I soak a rag in hot water and wrap the tip then place it in the steam pot, in the water, kind of combo steam/boil then when I take it out to bend it's in that hot wet rag that I take off as I put it in the jig this gives me a little longer time as I don't lose heat going from pot to form
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Jo I'd like to see you bend a big static like he's trying and only steam it ten minutes, for those big bends I steam about an hour and bend all at once, about 5/8" thick and two clamps
Here's a static im working on. 3/4 thick and that's after I removed some wood after bending it. Steamed 10 mins no problem no splinters. Also for alignment I steam the handle for 20 mins fixed that no problem no splinters
(http://i1354.photobucket.com/albums/q681/joec123able/9CFE3CEE-E174-4A3F-8892-D33FA712400F-92-00000001B5C691CD_zps286179cd.jpg)
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My family is from Missouri joe, I see the pic but I know from my personal experience that I can't get it to bend in ten minutes and get a static bend, except in a microwave, I've made bends on short wood in the microwave but even that took seven minutes and it heats from the inside out, not saying you can't do it but I know with all the wood I've bent I can't,
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My family is from Missouri joe, I see the pic but I know from my personal experience that I can't get it to bend in ten minutes and get a static bend, except in a microwave, I've made bends on short wood in the microwave but even that took seven minutes and it heats from the inside out, not saying you can't do it but I know with all the wood I've bent I can't,
It's all good man just wanted to prove that I'm not just saying it
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The bow is yeller, this is RO. Ones a stave ones a board. Staves bend a lot better. Specially if u have one ring on the belly. It looks like this lifted along the grain. Apples and oranges IMO.
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The bow is yeller, this is RO. Ones a stave ones a board. Staves bend a lot better. Specially if u have one ring on the belly. It looks like this lifted along the grain. Apples and oranges IMO.
I believe I said all of that in my original comment
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If the wood is green it will transfer the heat a lot faster than it will on dry wood. On 3/4" piece of seasoned osage I go a full 45 min steam. I have tried 20 and 25 min and it just wasn't long enough to let it bend. Fast moving steam over the bending area will also accelerate the heating process.
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I bent a green(down 4 hours) piece of OS yesterday. About 3/4" thick x 1 1/2" wide. Steamed for 15 min, bent like a noodle! I got more springback than with dryer wood. Will the green wood hold the bend as it seasons or can I expect even more springback?
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green wood should stay in the form or it can twist and straighten out your bend, and OS checks like a mad dog bites, good luck with it